C 五种初始化Vector的方法

资料来源: https://www.geeksforgeeks.org/initialize-a-vector-in-cpp-different-ways/

push_back初始化法

// CPP program to create an empty vector 
// and push values one by one. 
#include <bits/stdc++.h> 
using namespace std; 
int main() 
{ 
    // Create an empty vector 
    vector<int> vect; 
    vect.push_back(10); 
    vect.push_back(20); 
    vect.push_back(30); 
    for (int x : vect) 
        cout << x << " "; 
    return 0; 
}

初始值初始空间法

// CPP program to create an empty vector 
// and push values one by one. 
#include <bits/stdc++.h> 
using namespace std; 
int main() 
{ 
    int n = 3; 
    // Create a vector of size n with 
    // all values as 10. 
    vector<int> vect(n, 10); 
    for (int x : vect) 
        cout << x << " "; 
    return 0; 
}

初始值法

// CPP program to initialize a vector like 
// an array. 
#include <bits/stdc++.h> 
using namespace std; 
int main() 
{ 
    vector<int> vect{ 10, 20, 30 }; 
    for (int x : vect) 
        cout << x << " "; 
    return 0; 
}

拷贝其它Vector

// CPP program to initialize a vector from 
// an array. 
#include <bits/stdc++.h> 
using namespace std; 

int main() 
{ 
    int arr[] = { 10, 20, 30 }; 
    int n = sizeof(arr) / sizeof(arr[0]); 

    vector<int> vect(arr, arr + n); 

    for (int x : vect) 
        cout << x << " "; 

    return 0; 
}

迭代器拷贝其它Vector

// CPP program to initialize a vector from 
// another vector. 
#include <bits/stdc++.h> 
using namespace std; 

int main() 
{ 
    vector<int> vect1{ 10, 20, 30 }; 

    vector<int> vect2(vect1.begin(), vect1.end()); 

    for (int x : vect2) 
        cout << x << " "; 

    return 0; 
}